The contretemps surrounding Marianne Gingrich’s account — alleging that Newt Gingrich requested an “open marriage” as he was conducting an affair with Callista Bisek — points to a deep truth, beyond the political portent: societies that tolerate infidelity do a disservice to women.

A society that accepted open marriage would end up with more women than men being put in the uncomfortable position that Marianne Gingrich describes.

Marianne Gingrich’s pained interview with Brian Ross on ABC News is Exhibit A here. She obviously was not pleased by and has not recovered from Mr. Gingrich’s infidelity. Though we cannot know what was going through his mind at the time, it is certainly plausible that the spirit of the ’70s — when open marriage and serial divorce became fashionable — helped to shape and legitimate his own pattern of serial infidelity and divorce throughout much of his adult life. And it’s equally plausible that he did indeed pressure his wife for a ménage à trois — if Marianne is to be believed — in part because he had imbibed that ’70s spirit.

The open marriage ethic that was celebrated in the ’70s is particularly problematic for women because men tend to be more interested in multiple sexual partnerships — as a wide body of social scientific research tells us. For instance, in the United States today, women are significantly more likely to express opposition to infidelity and significantly less likely to engage in it. In the 2000s, only 10 percent of married women, compared with 16 percent of married men, reported that they had been unfaithful to their spouse, according to the General Social Survey.

So a society that came to tolerate open marriage would probably end up with more women than men being put into the kind of uncomfortable position that Marianne Gingrich describes. And that’s unfair to women.

Open marriage is also likely to be a terrible idea for children. A growing body of research suggests that children are harmed when they are exposed to a revolving cast of caregivers and partners. For example, a recent federal report found that children living with one parent and an unrelated romantic partner were about 10 times as likely to be sexually, physically or emotionally abused, compared with children living with their own married, biological parents.

Thankfully, at least when it comes to marital fidelity, the spirit of the ’70s seems to be in retreat. Since the 1970s, the public has become increasingly intolerant of marital infidelity, and the General Social Survey suggests that there has been no recent uptick in infidelity. For the sake of the nation’s women and children, let’s hope it stays that way.